This type of device makes it possible to mix components without reducing volume, and thus without setting up excess pressure liable to squirt the mixture out through the opening.
Japanese utility model 2 503 369 discloses a device of that type, in which the shutter drops to the bottom of the lower container at the end of relative rotation between the two containers. The shutter can then become caught in the passage if the device is turned over, thereby impeding dispensing of the mixture, particularly if the mixture is viscous.
Also, French patent application No. 2,691,950discloses a device with two containers including a moving shutter which, at the end of its displacement, bears against a shoulder of an actuator member mounted on the upper container. In that device, the above-mentioned drawback does not exist. However, the shutter extends over substantially the full height of the upper container and turns out to be expensive to produce if said container is large in size. The relatively great length of the shutter also gives rise to considerable twisting thereof during actuation, and that can lead to jamming. In addition, the shutter is screwed at its bottom end onto a chimney which co-operates with the upper container to form a groove in which the component contained therein can be retained without mixing with the other component.
German patent DE 44 36 863 C1 discloses a two-container device that is relatively complex in structure, having two shutters which move apart from each other during relative rotation of the containers.